RIOFH - Repository of Institute of General and Physical Chemistry
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Effect of modified atmosphere packaging on selected functional characteristics of Agaricus bisporus
No full textMushrooms are proven as a functional food due to their numerous beneficial effects on human health. Contemporary consumers purchase cultivated mushrooms that spend some time on the shelf, which makes it questionable whether this food can still be called "functional". An examination was performed on selected characteristics of white and brown (Portobello) Agaricus bisporus stored in commercial (air) and three modified atmosphere packagings (MAP): high nitrogen, low carbon dioxide and low oxygen packaging. The amount of ascorbic acid decreased throughout 22 days for both varieties, especially in the white variety stored in commercial packaging. Similarly, total flavonoids decreased, although not to a significant degree. Metal chelating ability was pronounced throughout the storage period, with minor changes in the case of the brown variety. Diabetes-connected enzymes were inhibited by A. bisporus, while inhibition was significantly higher toward alpha-amylase. Nitrogen-rich packaging suppressed alpha-amylase and stimulated alpha-glucosidase in the white strain. Both the commercial packaging and the MAP samples exhibited changes in their functional characteristics over three weeks of cold storage. MAP, especially the low oxygen packaging, provided the best option for the preservation of the majority of functional characteristics examined in this research. Enzymes activities appeared to be more specifically tuned, and dependent on parameters not covered here. Brown variety was more resistant to environmental changes with respect to its functional characteristics. [GRAPHICS]
New concept of fortified yogurt formulation with encapsulated carrot waste extract
No full textHigh yogurt consumption worldwide has opened the opportunity for designing a new concept of this fermented dairy product as an extremely valuable functional food item, fortified with bioactive components such as carotenoids. In this way, daily diets can become more effective in reducing diseases associated with nutritional deficiencies as well as alleviate the problem of accumulation of food by-products that are rich in bioactive components. In this study, after the extraction of carotenoids from carrot waste (CW) and complete characterization, the encapsulation process was carried out by electrostatic extrusion. Two concentrations of completely characterized CW beads (2.5 and 5 g/100g) were added to yogurt during the final step of yogurt preparation. Comparative studies of control and fortified yogurts were executed during a storage period of 28 d at 4 C. Yogurt fortification with both concentrations provides a part of beta-carotene recommended daily intake. Overall, microbiological and physico-chemical properties of the fortified yogurts were well-maintained during the storage period. The encapsulated carotenoids considerably improved the antioxidant activity of the yogurt; therefore, it can be used for the development of fortified yogurt with high nutritional properties
Prediction of mechanical extraction oil yield of new sunflower hybrids: artificial neural network model
No full textBACKGROUND Sunflower seeds are in the top five most abundant oilseeds in the world, as well as sunflower oil in the edible oils group. Recently, increasing attention has been paid to cold-pressed sunflower oil because less processing is involved and no solvent is used. The present study was carried out to investigate dimensions (length, width, thickness), firmness, general (moisture content and hull content, mass of 1000 seeds), gravimetric (true and bulk density, porosity) and geometric characteristics (equivalent diameter, surface area, seed volume, sphericity) of 20 new sunflower hybrid seeds. Steps to determine most of these parameters are quite simple and easy since the process does not require long time or special equipment. RESULTS Principal component analysis and cluster analysis confirmed differences in the mentioned characteristics between oily and confectionary sunflower hybrid seeds. One of the major differences between two groups of samples was in extraction oil yield. Mechanical extraction oil yield of the oily hybrid seeds was significantly (P LT 0.05) higher (from 68.72 +/- 4.21% to 75.61 +/- 1.99%) compared to confectionary hybrids (from 20.10 +/- 2.82% to 39.91 +/- 6.23%). Extraction oil yield values are known only after oil extraction. CONCLUSION Knowledge of the extraction oil yield value before the mechanical extraction enables better management of the process. By application of the artificial neural network approach, an optimal neural network model was developed. The developed model showed a good generalization capability to predict the mechanical extraction oil yield of new sunflower hybrids based on the experimental data, which was a main goal of this paper
Contemporary wine consumption: Role of intrinsic and extrinsic attributes in shaping consumers' preferences and behavior
No full textWine can be produced from many different grape varieties, which strongly influence the quality and style of wine. Since ancient times, wine has been traditionally produced by different technologies, depending on local or regional traditions. It seems the reasons for the popularity of this alcoholic drink all over the world lie not only in its delicious aroma/flavor, but also in the belief that a moderate intake of wine is recommended since it has potential health-promoting and disease-preventing effects. As global wine consumption is constantly increasing, winemaking has spread across the world to novel wine-producing areas. Therefore, an upward trend is to protect the geographical origin and other aspects of wine production in order to avoid fraud. The purpose of this chapter is to investigate the influence of different factors that shape consumers' wine consumption patterns and to provide insight into the most important aspects of purchasing decisions and behavior on different consumption occasions. Special attention is placed on extrinsic (e.g., labeling, packaging, brand, price, and country of origin (COO)) and intrinsic (e.g., color, flavor, smell, and appearance) attributes of wines, and also on the influence on consumption patterns (perceived quality of the wine, willingness to pay, and purchasing intention). By identifying the most important drivers of wine consumption, wine producers should be able to segment wine consumers based on their preferences and consumption habits and define the most effective marketing strategies and promotional programs for their products
Fine-tuning of conductive and dielectric properties of polypyrrole/TiO2 nanocomposite-coated polyamide fabric
No full textStructural, conductive and dielectric properties of hybrid Polypyrrole (PPy)-TiO2 nanocomposite-coated polyamide fabric (PA-PPy/TiO2) synthesized by in-situ oxidative polymerization of pyrrole on the surface of polyamide in the presence of colloidal TiO2 NPs (d similar to 4.5 nm) have been studied. Raman spectra confirmed salt form of PPy in both neat PPy and PPy/TiO2-coated PA fabric and indicated its complete coverage. SEM/EDX analysis confirmed presence of TiO2 NPs and changes in granular structure of PPy deposited on the surface of PA fiber depending on the amount of TiO2 NPs. The PA-PPy/TiO2 nanocomposite sample with lowest content of TiO2 NPs (6.79 At.% Ti) showed highest conductivity (similar to 10(-6) S/cm) and dissipation factor (tan delta) in the entire frequency range. The lowest amount of TiO2 NPs in the PA-PPy/TiO2 nanocomposite induced two to four orders of magnitude higher tan delta value, compared to neat PPy covered PA fabric, depending on the frequency range. Frequency dependence of real (epsilon') and imaginary part (epsilon '') of the complex permittivity for neat PA and PPy/TiO2-coated PA fabrics follow the trend of changes in dissipation factor for the same TiO2 NPs concentrations. The presence of TiO2 NPs could be exploited for tuning the conductive and dielectric properties of a conductive layer
Polarography as a technique of choice for the evaluation of total antioxidant activity: The case study of selected Coprinus Comatus extracts and quinic acid, their antidiabetic ingredient
No full textThis study was focused on in vitro screening of the total antioxidant activity of the selected extracts of the mushroom Coprinus comatus and quinic acid, one of their antidiabetic ingredients, by an uncommon electrochemical assay. Indeed, direct current (DC) polarographic HydroxoPerhydroxo Mercury(II) Complex (HPMC) assay based on decrease of anodic limiting current originating from HPMC formation in alkaline solutions of hydrogen peroxide at potential of mercury dissolution, observed upon gradual addition of antioxidants, was applied herein for the estimation of the natural products' antioxidativity. Quinic acid was found to exhibit most promising antioxidant potential (4.0 +/- 0.2%mu L-1) being approximate to 2-fold more active than the screened C. comatus extract samples. Actually, such a finding puts some light on the antioxidativity of cyclic polyols, well understimated class of organic compounds, compared to aromatic (poly)phenolics. As a low cost, easy-to handle and accurate this polarographic assay may be thoroughly recommended for much broader use
The morphological and compositional changes of bimetallic Ti/Al thin film induced by ultra-short laser pulses
No full textResults regarding morphological and compositional changes of bimetallic thin film (BMTF), composed of aluminium (Al) and titanium (Ti) nano-layers, by single fs laser pulses, are presented. Laser irradiation was conducted in the air with focused, linearly polarized laser pulses, the duration being 300 fs, wavelength 515 nm, and pulse energy up to 1.2 mu J. Effects of the variations of the pulse energy on the changes were studied. In the experiment, single pulse energy values from 0.03 to 0.08 mu J caused ablation-photomechanical spallation of the upper part of BMTF layer from the Si substrate, without ablation of the whole film. Irradiation at higher pulse energies gradually removed the whole BMTF and even a part of the Si substrate. We explained the influence of different electron-phonon dynamics, in the case of multilayered thin films composed of Al and Ti, on BMTF ablation. Damage/ablation threshold, which is minimal pulse energy/fluence sufficient for starting ablation, was calculated
Osmotic dehydration in sugar beet molasses-food safety and quality benefits
No full textIn recent year’s osmotic dehydration as a method of food preservation is drawing more attention due to many advantages regarding low energy processing conditions, mild temperatures and the possibility of reusing waste material. One of the most important factors that have a major influence on the efficiency of the osmotic dehydration process is a selection of the most convenient osmotic solution. At the Faculty of Technology, University of Novi Sad, sugar beet molasses has been introduced as an osmotic solution and turned out to be very efficient for the osmotic treatment of both animal and plant row materials. Reasons that make molasses an excellent osmotic medium are high content off dry matter (80% w/w) and specific chemical composition. Great amount of water and high aw value make food perishable and reduce its shelf life. By treating raw food material with sugar beet molasses as an osmotic solution the water content has been significantly reduced as well as aw value making food safer and longer-lasting. The microbiological profile of food material osmotically treated in molasses indicated that osmotic dehydration is a hygienically safe method and obtained products are safe for further processing. Comparing molasses with other conventional osmotic solutions it has been shown that molasses reduce the total amount of microorganisms in a larger scale than sugar and salt solution do. Sugar beet molasses has rich nutritional composition and during the osmotic process, those nutrients penetrate into treated material and improve its chemical composition, especially the content of minerals. In comparison to traditional osmotic solution osmotic dehydration treatment in molasses leads to higher amount of important minerals in both plant and animal treated material improving their functional properties. Osmotic dehydration in sugar beet molasses has proven to be valuable not only from food safety but from food quality aspects as well
Analysis of lead-based archaeological pottery glazes by laser induced breakdown spectroscopy
No full textThe aim of this study was to demonstrate the potential of Laser-Induced Breakdown Spectroscopy (LIBS) in the analysis of pottery shards, which are commonly the most abundant artefacts recovered at archaeological sites. The analytical capability of LIBS in identification of elements characteristic to inorganic pigments used for decoration was assessed. Based on the specific elements detected in the LIBS spectra of glazes, correlations between the elemental composition of the glaze and the colours of the glazed surface were established. The results were in accordance with the previously reported Energy Dispersive X-ray Fluorescence (EDXRF) and Raman analyses of some of the samples, and with the presently performed XRF analysis. Two important para-meters for plasma characterization, temperature and electron number density, were estimated from the spectral data. A potential use of LIBS for depth profiling was also investigated by analysing the silicon to aluminium intensity ratio as a function of the number of laser shots applied. Profilometry analysis of the damages created on the glazed surfaces by laser shots was used to estimate the average ablation depth and ablated mass